1. Field of the Invention
The present invention relates to a zoom lens system for a compact camera in which a back-focal distance is restricted. In particular, the present invention relates to a zoom lens system of a relatively large aperture in which the zooming ratio is approximately 2; the F-number at the wide angle extremity is approximately 2.8; and the F-number at the telephoto extremity is approximately 3.5 to 4.
2. Description of Related Art
In general, a zoom lens for a compact camera whose zooming ratio is approximately 2 usually employs two lens groups. In such a known zoom lens, the F-numbers at the wide angle extremity and the telephoto extremity are around 3.5 to 4 and around 6.7 to 8, respectively. If a mechanical aperture is designed to be large in order to obtain a small F-number at the telephoto extremity in a zoom lens having two lens groups, it results in a zoom lens size which is large and has considerable aberrations which are difficult to correct.